The chance to isolate stem cells form human tissues today is controversial and much-discussed. The definition itself of stem cell, a cell able to self-renew and differentiate towards all the different cytotypes of the organism from which it derives, does not fit with the antigenic and functional characteristics of the adult stem cells, up to now collectable in humans after the birth. On the side of the “self-renewing”, actually, adult stem cells that have been isolated up to now, do not display unlimited proliferation ability and, on the other side, differentiation ability has been hardly overcome the multipotency (the ability to differentiate in all the cytotypes that come from the same germinal layer) or pluripotency (the ability to differentiate in the cytotypes that come from different germinal layers too), without reaching the totipotency (the ability to differentiate in every cytotype); the latter is an ability owned by zygote and by cells of the blastocyst, leading to the first steps of human development. On the other hand, the chance to handle cells collected from human embryos for therapeutic and research applications often collides with technical, ethic and legal difficulties. For these reasons the chance to isolate in adult humans undifferentiated cytotypes, represents not only an interesting experimental model of cellular differentiation and for cancer related issues, but also an important therapeutic tool to cure tissue degeneration-based diseases, caused by quantitative and qualitative defects.
The stem cells are cytotypes characterized by:                1) unlimited self-renewal;        2) differentiation ability towards numerous cytotypes.        
With respect to the prior art, represented by WO 03/066840 that includes follicular cerotype, this invention shows the following differences:                1) Antigenic pattern and selection methods of the cells. WO 03/066840 does not disclose any selection, whereas the method of the invention uses selection by cytofluorimetry of embryonic stem cells, through antigens detection such as SSEA-4, TRA 1-60, TRA 1-81, CD133, CD90, flk-1. In this way it is possible to obtain a homogeneous population of embryonic cells.        2) Culture methods, cellular proliferation and differentiation; actually WO 03/066840 describes the techniques to collect a cellular population that contains only in a small part adult stem elements, whereas the selection method according to the present invention allows the preparation of an homogeneous embryonic-like stem cells population.        